Small Coil Winder Project

[DaftFader]

Wire tensioning is another problem. Ideally the wire needs back tension, like a tape recorder, continually pulling back so varying shape of the spool doesn't let the wire go slack.

For very thin wire Jim bought a commercial job. It uses magnetic reluctance as a brake and a spring wire for back-tension.

I made a machanically braked (using a band brake) machine that seems to work ok for thicker wire (0.25+) , but lacks back-tension.

 

[abbey road d enfer]

Wire tensioning is another problem. Ideally the wire needs back tension, like a tape recorder,

Indeed. the big problem is that contrary to a tape recorder, the instant speed varies extremely rapidly, oblong windings (such as gtr pickups) being the worst. The enemy is inertia. It takes a very light system to absorb these variations, while still providing enough damping. In pictures I've seen vey simple systems constituted of a pulley affixed to a piano-wire spring.
I wander if an active solution could be used, since the required function is similar to a negative resistance (the higher the speed the lower the braking force).

 

[DaftFader]

Yes bobbin shape is a major issue. I had an idea to modulate the speed of the winding to compensate.

 

[abbey road d enfer]

Yes bobbin shape is a major issue. I had an idea to modulate the speed of the winding to compensate.

You would need some kind of sensor. Either an instant-speed transducer (optical wheel) and/or a wire tension sensor. That is basically the system employed on the latest generation of tape machines, but with very different ballistics. Not a minor feat...

 

[gyraf]

I have good results with simple friction tensioning - running the wire through a piece/patch/bundle of microfiber cloth, then applying mechanical pressure to the outside of this bundle to vary friction. Quite usable down to at least 0.06mm - but off course not real back tension if that is needed..

/Jakob E.

 

[Latti]

I see good possibilities in DC motor braking. the tension can be easily regulated even analogically

 

[Bo Deadly]

Or maybe modulate the bobbin instead of the wire? Meaning the rotor moves the bobbin relative to wire so that it minimizes rapid sheering forces. Imagine the movements required to leave the wire fixed in space. The rotor assembly would need to be some sort of compound gear I suppose. But that might be just the trick needed to neatly wind really small high inductance coils.

 

[DaftFader]

Abbey rd...

I have a rotation sensor so all I need to do , is sync the bobbin to the sensor (i.e. home spindle and align bobbin) then send acceleration and speed settings every quarter turn (or more usefully, store a rotation profile in the PIC to do the same ).

 

[abbey road d enfer]

Abbey rd...

I have a rotation sensor so all I need to do , is sync the bobbin to the sensor (i.e. home spindle and align bobbin) then send acceleration and speed settings every quarter turn (or more usefully, store a rotation profile in the PIC to do the same ).

Correct! Tell us when you make it work.

 

[DaftFader]

Correct! Tell us when you make it work.

The emphasis on the all in my message was ironic.

Sending updates from the controller would severely limit speed and rewriting the PIC would require motivation which is severely lacking ;-)

 

[abbey road d enfer]

The emphasis on the all in my message was ironic.

That's how I took it. I should have added an emoticon, to make it clear.

Sending updates from the controller would severely limit speed

I think the ballistics of a DC motor would make the system unstable, and steppers are too slow.

and rewriting the PIC would require motivation which is severely lacking ;-)

It's often the dominant factor in DIY.

 

[gyraf]

Perhaps possible by applying PID on a brushless motor, then allowing it grotesque amounts of peak-power-when-needed?

This how camera stabilizers are done, react surprisingly quickly even at heavy loads..

/Jakob E.

 

[beatnik]

Have been wondering if there has been any progress about this project and if we can still expect a release at some point ?

 

[Cyril Jones]

Hi Gyraf is quite correct. Winding prototype Lustraphone bobbins with 47SWG wire required a little tension on the wire, a small piece of soft sponge applied the necessary tension, held the wire in place when the winding process was stopped to terminate the wire. A small jig to hold a folded piece of material worked wonders. I guess it would work for heavier gauges.

Cyril Jones

 

[Tubetec]

Tanac tensioners,
the design has been pirated ,
a small fishing rod with a roller at the top provides the back tension ,low friction guides and magnetic reluctance allows the wire to be wound under near constant tension. Servo driven is also available

 

[abbey road d enfer]

Tanac tensioners,

Googling that returns nothing, do you have a link?

 

[Tubetec]

Google , there away with the faries ,
first hit on my search,
https://tanac.net/

 

[abbey road d enfer]

OK. The reason why I had no hit is that there are about a zillion pages for "tabac" (tobacco).
Now, the Tanac site seems to have no information past the Home page...

 

[Tubetec]

try this ,
https://www.tanac.co.uk/english_mt.html

 

[abbey road d enfer]

Thanks for the link.
This one seems particularly impressive
https://www.tanac.co.uk/english_etc.htmlI understand it's definitely not for DIY, but nonetheless interesting.